Android中修改TabLayout底部导航条Indicator长短的方法

前言

对于Tablayout相信大家都不陌生，在开发中使用的应该很频繁了，但是底部导航条长短是固定死的，需要自己来改动长短，找了半天没找着方法，看了下官方建议，可以通过映射来修改自己想要的长短，其实也就几行代码的问题。

看代码：

 public static void setIndicator(Context context, TabLayout tabs, int leftDip, int rightDip) {
  Class tabLayout = tabs.getClass();
  Field tabStrip = null;
  try {
   tabStrip = tabLayout.getDeclaredField("mTabStrip");
  } catch (NoSuchFieldException e) {
   e.printStackTrace();
  }

  tabStrip.setAccessible(true);
  LinearLayout ll_tab = null;
  try {
   ll_tab = (LinearLayout) tabStrip.get(tabs);
  } catch (IllegalAccessException e) {
   e.printStackTrace();
  }

  int left = (int) (getDisplayMetrics(context).density * leftDip);
  int right = (int) (getDisplayMetrics(context).density * rightDip);

  for (int i = 0; i < ll_tab.getChildCount(); i++) {
   View child = ll_tab.getChildAt(i);
   child.setPadding(0, 0, 0, 0);
   LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.MATCH_PARENT, 1);
   params.leftMargin = left;
   params.rightMargin = right;
   child.setLayoutParams(params);
   child.invalidate();
  }
 }

leftDip和rightDip是左右间距，根据自己的需要来设置，直接调用即可。

很多同学都遇到问题，这里附上源码，大家可以看看：

package com.example.donghe.myrefreshview;

import android.app.Activity;
import android.content.Context;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TableLayout;

import java.lang.reflect.Field;

public class MainActivity extends AppCompatActivity {

 private static int TAB_MARGIN_DIP = 11;
 TabLayout tableLayout;
 ViewPager viewPager;
 RankingPagerAdapter adapter;
 String [] strings = {"皇帝","丞相","尚书","太监"};
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tableLayout = (TabLayout) findViewById(R.id.tabs_ranking);
  viewPager = (ViewPager) findViewById(R.id.container_ranking);

  adapter = new RankingPagerAdapter(getSupportFragmentManager());
  viewPager.setAdapter(adapter);
  tableLayout.setupWithViewPager(viewPager);
  tableLayout.setTabTextColors(getResources().getColor(R.color.black), getResources().getColor(R.color.red_pre));
  tableLayout.setTabsFromPagerAdapter(adapter);
  setIndicator(this, tableLayout, TAB_MARGIN_DIP, TAB_MARGIN_DIP);

 }

 private class RankingPagerAdapter extends FragmentStatePagerAdapter {
  public RankingPagerAdapter(FragmentManager fm) {
   super(fm);
  }

  @Override
  public Fragment getItem(int position) {
   return new FuelFragment().newInstance(position, strings[position]);
  }

  @Override
  public int getCount() {
   return strings.length;
  }

  @Override
  public CharSequence getPageTitle(int position) {
   return strings[position];
  }
 }

 public static void setIndicator(Context context, TabLayout tabs, int leftDip, int rightDip) {
  Class tabLayout = tabs.getClass();
  Field tabStrip = null;
  try {
   tabStrip = tabLayout.getDeclaredField("mTabStrip");
  } catch (NoSuchFieldException e) {
   e.printStackTrace();
  }

  tabStrip.setAccessible(true);
  LinearLayout ll_tab = null;
  try {
   ll_tab = (LinearLayout) tabStrip.get(tabs);
  } catch (IllegalAccessException e) {
   e.printStackTrace();
  }

  int left = (int) (getDisplayMetrics(context).density * leftDip);
  int right = (int) (getDisplayMetrics(context).density * rightDip);

  for (int i = 0; i < ll_tab.getChildCount(); i++) {
   View child = ll_tab.getChildAt(i);
   child.setPadding(0, 0, 0, 0);
   LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.MATCH_PARENT, 1);
   params.leftMargin = left;
   params.rightMargin = right;
   child.setLayoutParams(params);
   child.invalidate();
  }
 }

 public static DisplayMetrics getDisplayMetrics(Context context) {
  DisplayMetrics metric = new DisplayMetrics();
  ((Activity) context).getWindowManager().getDefaultDisplay().getMetrics(metric);
  return metric;
 }

 public static float getPXfromDP(float value, Context context) {
  return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value,
    context.getResources().getDisplayMetrics());
 }
}

Fragment：

package com.example.donghe.myrefreshview;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;



public class FuelFragment extends Fragment {

 public static String TAB_POSITION;
 public static String TAB_NAME;
 private String tabId;
 private int tabPosition;

 public FuelFragment() {
 }

 public static Fragment newInstance(int tabPosition, String tabName) {
  FuelFragment fragment = new FuelFragment();
  Bundle bundle = new Bundle();
  bundle.putInt(TAB_POSITION, tabPosition);
  bundle.putString(TAB_NAME, tabName);
  fragment.setArguments(bundle);
  return fragment;
 }

 @Nullable
 @Override
 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  return inflater.inflate(R.layout.layout, container, false);
 }

 @Override
 public void onActivityCreated(@Nullable Bundle savedInstanceState) {
  super.onActivityCreated(savedInstanceState);
  tabPosition = getArguments().getInt(TAB_POSITION, 0);
  tabId = getArguments().getString(TAB_NAME);
  ((TextView) getView().findViewById(R.id.text)).setText(tabId);
 }
}

布局：

总结

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